Pobation



NOV. 15, 1927. 1,649,005

L. T. wlLcox OVEN Filed May 16. 1925 mm 3 Sheets-Sheet l v INVENTOR Zi/V/S .fW/zcox ATTOR EYS.

Nov. 15, 1927.

L. T. WILCOX OVEN Filed May 16. 1925 3 Sheets-Sheet 3 A ORNEYS.

Patented Nov. 15, 19 7.

UNITED STATES PATENT OFFICE.

LEV/IS T. JVILCOX. OF PEEKSKILL. NET? YUEK. ASSIGNOB, TO WZLCOX PATENTS COR- PORATION, OF PEEKSKILL, 1511353!- YORK, A COEPQBATION OF NEW YORK.

OVEN.

Application filed May 16, 1925.

This invention relates to ovens, and particularly to the portable type which may be placed over open burners, such as gas and liquid petroleum burners.

An object of the invention is to provide an improved oven which may be manufactured largely from sheet metal; which will be rela tive-ly strong, eliicient, durable and inexpensive; and in which the various parts may be formed and assembled in a relatively simple manner.

A further object is to provide an improved oven of double burner size or larger than the usual single burner size. which may he ell ectively and etticiently utilized upon a single burner, and in which a uniformity of tem perature throughout baking chamber is possible.

A further object is to provide an improved oven in which the hot gases from the burner entering the oven for heating purposes will be directed and conducted in such a manner as to provide a maximum uniformity of term perature throughout the oven.

Various other objects and advantages will be apparent from the following description of several embodiments of the invention. and the novel features will be particularly point ed out hereinafter in connection with the appended claims.

The invent-ion comprises the various details which will be explained in the accomianying description of the several embodiments of the invention.

In the accompanying drawing:

Fig. 1 is a longiti'idinal sectional clcvation through an oven constructed in accordance with the invention and including an improved heat spreader cnabling use of the oven upon a single burner;

Fig. 2 is an end elevation of the same;

Fig. 3 is a. transverse sectional elevation of the same. with the section taken approximately along the line 3--3 of Fig. 1:

Fig. 1 an end elevation of one corner of the oven showing the manner of attaching the door thereto. the door being in position for attachment to the hinge elements which are permanently carried by the oven casing;

Fig. 5 is a section through one oi the hinge c nnections through the door and casings, the section being taken substantially along the line fi -5 at Fig. 2;

Serial No. smear.

Fig. 6 is a longitudinal sectional plan through a portion of the oven, the section being taken substantially along the line 6-6 of Fig. 1;

Fig. 7 is a side elevation of a portion of the oven and illustrating the manner of connecting the handle thereto;

Fig. 8 is a sectional elevation through the same with the section taken substantially along the line SS of Fig. 7;

Fig. 9 is a sectional plan through the portion or the door of the oven containing the latch, the section being taken substantially along the line 9 9 of Fig. 2;

Fig. 10 is a sectional plan through a portion of the oven, with the section taken substantially along the line 1010 of Fi 2;

Fig. 11 is a sectional plan on a slightly larger scale through a portion of the door, the section being the same as that taken approximately along the line 11-11 of Fig. 2 and illustrating by means of the dotted lines the manner of forming the marginal bead thereon;

Fig. 12 is a sectional plan through a portion of the oven illustrating the manner of mounting a. transparent window plate on the door, the section being taken substantially along the line 1212 of Fig. 8;

Fig. 13 is a plan of an improved grate forming a part of the invention;

Fig. 14 is a sectional elevation of a portion ol the grate, with the section taken substantially along the line 14.14 of Fig. 18.

In the embodiment illustrated in Figs. 1 to 14. the oven casing is provided with outer and inner shells 1 and 2 of sheet metal. The outer shell is termed by bending a strip of sheet metal into the desired tubular form and closing one end of the same by a sheet metal end wall which is seamed thereto at 1. The end wall 3 has formed therein an internal shoulder 5 which is spaced from and parallel to the margin. and the inner shell tits into the area defined by said shoulder and is held in spaced relation to the side walls hv said shoulder.

The inner shell is also formed by bending a strip oi sheet metal into tubular shape and closing one end by a wall 6 which is seamed thereto at 7, the portion of the end wall 6 within the peripheral seam 7 being depressed and the seam itseli fitting within the peri h eral abutment formed by the shoulder 5, so that the end walls 3 and (l of the outer and in ner shells will be spaced apart to some extent for insulating purposes. The space between the open ends of the inner and outer shells at the other end is closed by a frame-like piece of sheet metal 8, which is seamed over the adjacent ends of the inner and outer shells. A door 9 is disposed across the open end of the tubular casing and may be formed of two stretches or plates 10 and 11 of sheet metal which are spaced apart for a consul-- erable portion of their area in order to provide an interposed dead air space for insulating purposes. The two stretches 10 and 11. of sheet metal of the door are brought into abutting relation face to face along their margins, as at 1, and one or the stretches, such as the outer stretch 10 extends marginally to a reater extent than the inner stretch, being tolded back upon the marginal edge of the inner stretch, as at 13, to form a seamed connection between them. This seamed edge is shown in Fig. 11 by the dotted lines, and after being thus "formed the two abutting marginal portions at 12 are rolled backwardly into the form of a bead 14;, which extends marginally ol? the door, reinforces it against lateral tienure, and fits into a depression 15 provided in the inner marginal portion of the outer face of the frame end 8, as sho n clearly in Figs. 1, 6, 10 and 12. The bead lat by its engagement in the marginal depression in the enc frame wall 8 assists in holding the door against lateral movement when in closed position. Suitable hinges 16 are secured to thelower stretch of the end frame 8, with the tree arms 17 of the hinges extending upwardly for a short distance in a direction across the door opening. The door 9 is provided along its lower edge with tl-shaped straps 18 torming, with the outer face of the door, sockets into which the free arms ll" of the hinges extend so as to form a separable connection between the door and the hinge. The arms 17 may be provided with slight struck out protuberances 19 which are adapted to snap into corresponding pressed concavities 20 provided in the inner face of the straps 18 in such positions that when an arm 17 is "fully within its socket with the door closed, the protuberance l9 thereon will enter or snap into the concavity :20 and yieldingly resist separation oi the arm from the socket. This construction, therefore, provides a detachable hinge connection between the door at its lower edge and the open eno of the casing, permitting swinging oi the door outwardly and downwardly in an opening direction.

llilong the upper margin of the door a handle base element 21 is rotatably mounted in the outer stretcher plate 10 of sheet meta-l forming the door, the inner end of the base element 21 carrying a bushing 92 9) and a locking arm 23 titted upon a noncircular end section :24 of the inr r end of the base element, the arm and bush ng being held thereon in a suitable manner such as by upsetting the material at the extreme inner end of the base element.

A suitable handle bail is hinged to the base element 21 to rotate it and the locking arm together. This locking arm extends its free end through a slot in the inner stretch ll of the sheet metal forming a part of the door. so as to project beyond the door opening when given one angular position,

and to be retracted within the limits of the door opening when rotated inlo another gular position. The inner shell 2 is provided with a slot 26 at its upper edge adjacent the door opening, into which slot the loch; ing arm 3 may more when rotated into its angular position where it projects beyond the door opening, and when so rotated will enter the slot and ser e as a latch for hold inathe door in closed position.

The door prov led above its lower hinged edge with a pair of lJ-shaped straps 27 which are secured against the outer face of the door at its side edges to provide, with the door face, a pair of horizontally extending sockets at the sides into which the angular ends 28 01 limit strips 29 are received. These limit strips extend from the sides 01' the door through apertures 30 in the outer end frame wall 8, and into the space between the outer and inner shells, the strips being arcuate with a center of curvature lying ap proximately in the axis of the hinge pintlc of the door, so that h. door may swing to and from closed position. without binding of the limit strips in the slots 30.

The inner ends of the limit strips are bent angularly as at 31, so as to engage against the inner face oi the end itran'ie wall 8 when the door swung forwardly and form stops to prevent further forw rd and downward movement of the door. ll hen the door is in its for ard and downw rd posi "ion. and the limit strips have been pulled outwardly to,

apprommately their maizin'nnn extent, their outer ends may be swung lat rally so as to be disengaged l ron'i the sockets formed by the straps 27, WfllCll will then permit disengement oi' the door from the hinge arms The straps 27 may be prorit d upon their inner faces with struclr out cavities (Fig. 2), Slll'lilll to the .ities :20 oi. the straps l8, into wh ch rarities protubcrances not shown) upon the angg ula r ends 28, similar to the protuberances 19 oi the hinge arms, may snap :tor yield angular ends of the limit sockets.

The door may be provided with two open windows 33 and 34-, the window 83 being larger. F or the window 33, the inner and strips within the holding the ion lit)

door, which borders the window outer stretches 10 and 11, forming the door, are seamed together as at 35, (Figs. 1 and 12) and a transparent plate 36 is confined across the window opening by a marginal retaining frame 37, (Figs. 1. 3 and 12), which overlies the margin of the transparent plate and fits against the inner face of the door. The portion of the inner face of the opening 33, is provided with a plurality of headed studs 58, which pass through keyhole slots 39 in the outward marginal edge of the retaining frame 37.

The keyhole slots 39 are similarly positioned so that the retaining frame may be applied to the studs or removed therefrom by sliding laterally, and the length of the studs between the heads and inner face of the door is such as to frictionally hold the retaining frame against lateral movementsuch as would cause disengagement from the stud... The larger ends of the keyhole slots are, of course, equal to or larger than the diameter of the heads of the studs, and the smaller ends of the slots are of less diameter than the heads of the studs.

The retaining frame 37 at its inner marginal edge presses resiliently against the transparent plate so as to hold it from vibration and effect a tight closure at. the window opening 33. The transparent plate 86 may be of any suitable material which will resist heat, such as glass which is manufactured to withstand high temperatures.

An instrument, such as a thern'ion'ieter enclosed in a casing 40, is disposed in the open window 3st of the door and this instrument :asing at its rear end is flanged outwardly as at 41 (see Fig. 3) so as to fit against the inner wall of the door, this flange having keyhole slots 42 which cooperate with headed studs 43, to removably mount the instrument in the door. The slots 42 are all similarly positioned so that to remove the instrument casing, it is merely necessary to rotate it a short angular distance to carry the. larger ends of the slots into alignment with the heads of the studs. over which they may then be passed during removal of the instrument casing. The stretch 10 of sheet metal forming the outer wall of the door, at the opening for the window 34 is preferably flanged inwardly as at *lsl (see Fig. 1), so as to avoid the presence of irregular edges Fitting the periphery of the instrument casing.

On the two sides of the casing adjacent the top thereof, a pair of metal plates l5 are secured in any suitable manner, such as by rivets or welding, and each plate has a tongue 46 cut into and struck up from the lower edge thereof. the ton gucs being buckled outwa *dly so as to form a spring hook under which a handle bail 47 may be snapped and retained. Each handle bail may be provided upon its outer end with an insulating or cold grip 48. and is angularly bent intermediate of its length as at 49, so that when the bails swing downwardly against the sides of the casing, the free ends will extend obliquely to such side walls as shown in Figs. 2 and 3. Thus. the insulating or cold grips 48 will always be held out of direct contact with the hot side walls of the casing.

\Vhen the oven is to be carried about or lifted by the handles, the handles are first swung upwardly into the positions shown in dotted lines in Fig. 3, and when the lifting forces are applied to the handles in those positions, the pull will be upwardly upon the tongues 46 and applied at the base ends thereof where they join the plates. so that there will be a mininnim of flexure placed upon the tongues during the lifting opera tions.

A plurality of strips 50 are secured along the side wall of the baking chamber of the oven so as to extend rearwardly from the door opening at dill'erent levels, being arranged in pairs on opposite sides, with the channels all 'lacing inwardly and horizontally, so that the pair in each horizontal plane will prei'ent opposing guide grooves in which grates may be rcmovably inserted by sliding them through the open door into the guide grooves.

The grates 51 are preferably formed by bending a stretch of metal ribbon into a closed loop frame (see Figs. 13 and 14) having an enclosed area extending approximately coextensive with the horizontal area of the interior of the oven, so that they may be inserted into the baking chamber of the oven and supported in the guide channels 50. The ends ol the stretch of ribbon forming the frame, which abut when the stretch of ribbon is bent into the closed loop form, may be secured together by any suitable method such as by welding to give a r:- gidity to the frame. In the type of oven illustrated, the horizontal area of the oven is in the shape of a rectangle, and the frame of the grate is correspondingly rectangular.

Two opposite side stretches of the closed loop frame are provided with spaced apertures 52, and grate bars 53 are provided at their ends with reduced tongues 54, which fit into the apertures 52 when the grate bars are inserted between the two apertured opposite stretches of the grate frame. The grate bars may be inserted between the opposite stretches of the frame with their tongues entering the apertures of the frame, while the ends of the frame are being brought togetherto complete the loop and before they are permanently fastened together.

The ribbon which forms the frame is preferably bent upon lines transversely thereof and in the plane of the faces, so that the planes of the ribbon forming the sides of the grate will be vertical, and the intermediate bars 53 will also be of the same width ribbon and vertical as illustrated. Vi hile it will be understood that simple recesses in the inner faces of the frame may be provided for receiving the tongues 54;, it is preferable to provide the apertures all the way through the ribbon, because the manufacturing process simpler.

The inner and outer shells are provided in their bottom walls with substantially aligned apertures 55 and 56 1 and 3) respectively, which are connected by a tu bular sheet metal wall 57. The lower end of the wall 57 is flanged inwardly, and the portion of the bottom wall of the outer shell bordering the aperture 56 is bent inwardly and backwardly upon the flange at the lower end of the wall 57. to form a seamed connection between them. The upper end of the wall 57 is connected by sheet metal seam to the portion of the bottom wall of the inner shell which borders the aperture 55. The wall 57, therefore, forms passage through the bottom part of the casing, through which the hot gases from burners over which the oven is placed may enter the baking chamber in the interior of the casing.

A plate 58 (Figs. 1 and. 3) of sheet metal is provided along two of its opposite side edges with seams 59 formed by bending under and backwardly the side marginal edges, and the other two marginal edges are flanged downwardly and double back as at 60, so as to form supporting walls or legs for spacing the plate 58 above a surface upon which it rests. The area of this plate with its flanges is such that it will fit within .the baking chamber upon the bottom wall of the inner shell, as shown in Fig. 3, with the seams 59 extending along the side walls of the oven, and the flanges 60 at the front and rear and serving to support the body of the plate 58 above the bottom wall of the inner shell.

A strip 61 of sheet metal is secured along two of its side edges to the under face of the plate 58, with the secured edges extending approximately parallel with or in the same general direction as the seams 59. The strip 61, however, is shorter than the plate 58 and is shorter than the length of the passage through the bottom of the casing, considered in its major dimension. The intermediate portion of the strip between the two secured side edges extends downwardly at each side as at 62, and then is bowed arcuately and upwardly to form a concave un der face, with the concavity increasing from approximately nothing at one end to a BULK- imum at the other end, so that the under concave face of the strip 61 will, in effect, be inclined upwardly from one end to the other as shown in Fig. 1.

The rear end portion of the plate 58 is provided with a plurality of apertures 63 which are rearward of the end of the strip 61. The plate 58 and the strip 61 secured beneath it, together form a heat spreader which extends across the passage through the bottom of the casing for spreading the incoming hot gases towards the margins of the baking chamber. The heat spreader illustrated in Figs. 1 to 6, is that employed where a relatively large oven, such as of a double burner size, is placed over one burner or source of heat. For example, as illus trated in Fig. 1, the oven has a depth greater than that usually employed for a single burner oven, and since the depth is greater than the width, it is impossible to place the burner in such a position that a maximum uniformity of temperature in the baking chamber will be obtained unless a special spreader, such as that illustrated is utilized.

In this construction, the oven will be placed over the burner, with the burner near the forward end of the oven so that the hot gases will enter the bottom of the chamber at a point illustrated by the arrows a in Fig. 1. The strip 61 and the plate 58 will dctlect the hot gases laterally to all of the margins of the plate 58, and the gases passing beyond the sides of the plate 58 will be able to pass upwardly around the seams 59 which. are spaced above the bottom Wall of the chamber by the flanges 60 located at the front and rear. (See Fig. 3 for the direction of travel in such laterally deflected gases as illustrated by the arrows.)

By reason of the inclined under face of the strip 61, a greater portion of the hot gases will be deflected toward the rear. than. toward the front, and the gases traveling toward the rear will pass partly under the sides and the rest upwardly into the baking chamber through the apertures 63 in the plate 58. (See l and 6.) By having the under face of the strip 61 concave tran-s verscly as well as inclined rearwardly, the strip will deflect a greater proportion of the hotgases to the rear instead of to the sides, and thus by varying the concavity and cf- .tective inclination, the proper distribution of the hot gases under normal conditions may be obtained, so that a maximum uniformity in temperature in the oven may be created The plate 58 is not provided with apertures at its forward edge, and the flange 60 at the forward edge will prevent the passage of gases directly against the door of the oven. The flanges 60 are preferably formed by bending the edge portions downwardly and then inwardly and baokwardly as shown in Fig. 1 so that the double thickness of the flange resulting will give greater rigidity. which is important because the spreader is supported entirely by the flanges 60 at the front and the rear. The strip 61,

of course, may depend into the passage through the bottom of the casing to some extent.

The side walls of the inner shell are provided adjacent their upper end, with a plurality of apertures 64:, arranged in a row from front to rear, so that the hot gases rising through the baking chamber may pass through the apertures G l into the space between the side walls of the inner and outer shells. The side wall-s of the outer shell are provided along their lower edge portion with a plurality of apertures 65, extending in spaced relation from front to rear, so that the hot gases from the space between the inner and outer shells may descend downwardly through the side walls of the oven and be discharged into atmosphere through the apertures 65. The hot gases in passing downwardly between the side walls of the casing will serve as a hot insulating blanket, preventing to some extent outward radiation of heat through the baking chamber, and will also radiate heat inwardly to some extent.

Referring particularly to Figs. 1 to 14, the oven when used is disposed over a source of heat so that the hot gases will pass upwardly through the forward part of the passage through the bottom of the oven, as indicated by the small arrows a in Fig. 1. The hot gases thus entering will be deflected approximately uniformly to the marginal portions of the oven, a considerable proportion going toward the rear due to the effective inclination of the strip 61, since the travel of the hot gases towards the furthest marginal parts of the oven must be facilitated if uniformity of temperature in the baking chamber is to be obtained. The gases thus entering will pass upwardly into the baking chamber and provide a tempera ture therein substantially uniform throughout its area.

The gases rise through the baking chamber, pass through the apertures 64, in the side walls of the inner shell, thence clownwardly between the two side walls of the inner and outer shells, and are discharged into the atmosphere through the apertures 65 in the lower edges of the side wall-s of the outer shell. The gases in traveling between the side walls of the oven will serve as a hot blanket for assisting in preventing outward radiation from the baking chamher, and will also radiate heat inwardly to some extent to maintain or increase the temperature within the baking chamber. By reason of the spacing of the lateral and rear end walls of the inner and outer shell-s, heat radiation from the baking chamber will be reduced to a minimum.

The door of the baking chamber may be opened by rotating the latch handle 35 to retractthe latch arm 28 from the aperture 26 in the inner shell, whereupon the door may be swung forwardly and downwardly to the extent permitted by engagement of the angular ends 31 of the limit strips 29 with the inner face of the end frame wall 8. if one desires to remove the door, it is merely necessary, when the door is in its open position, to pull the forward ends of the limit strips 29 out from the sockets formed by the straps 27, whereupon the door may be lifted off the hinge arms 17. The door is reconnected to the casing by the reverse of these movements.

The oven may be lifted and moved while hot by the handles 47, but it will be observed that the grips of the handles will never come in direct contact with the hot side walls of the oven. While the grips of the handles above referred to are usually of insulating material, it will be understood that any of the usual cold handle grips whether of insulating or non-insulating material may be used, if desired.

The user will be able to observe through the transparent plate 36 the progress of the baking operation without the necessity of opening the door and the temperature will be indicated by the instrument 40 mounted in the door. The instrument and transparent plate may be readily removed by reason of the keyhole slot connections de scribed, so that the changing or replacing of the transparent plate and instrument are relatively simple operations. The hinged connections between the handles and the oven walls are exceptionally simple, since the plates 45 employed may be struck from flat metal and the tongues formed by suitable dies, and the handles may be readily connected thereto by springing them beneath the tongue hooks 46.

The grates are formed entirely of metal ribbon, that is, strips of flat metal which are cut to the desired length, formed into the closed loop, with the grate bars of the same material interposed and supported in apertures in the two apertured sides or stretches of the, closed loop frame. This provides a very inexpensive, strong, rigid, and durable construction, with smooth upper and lower faces, so that the grate bar may be used with either face up. The use of the channel strips as guides and supports are relatively inexpensive, since such strips may be purchased from standard stocks, the same bein formed in quantity by rolling the hot meta? at the steel mills.

It will be understood that with this construction of oven, the heat spreader of Figs,

closed and effect a closed joint between the door and the end of the casing. The en gagement of the bead in the depression also prevents lateral play of the door when the latter is closed.

The casing and door are made practically entirely of sheet metal, which is relatively inexpensive, and the manner of forming the seams which is illustrated is such that the seams may be formed readily by the usual metal working machinery.

It will be obvious that various changes in the details, which have been herein described and illustrated for the purpose of explaining the nature of the invention, may be made by those skilled in the art within the prin ciple and scope of the invention as expressed in the appended claims.

I claim 1. An oven, comprising a tubular casing having a baking chamber therein, the bottom wall of the casing having a passage therethrough for the entrance into the baking chamber of heated gases, a heat spreader supported across the passage for deflecting the heat to the marginal portions of the baking chamber, said spreader having the wall surface encountered by the rising heated gases inclined in a direction to deflect a large portion of the gases toward one por tion of the oven.

2. In an oven, a tubular eloi'igated casing having a baking chamber therein, the bottom wall of the casing having a passage for the entrance of heated gases, and a heat spreader supported across said passage for directing the entering heated gases to the marginal portions and having a wall for directing a considerable portion of the heat ed gases toward one marginal section of the oven whereby-when the oven is utilized over a single source of heat that is not centrally placed under said passage, the spreader will direct an increased proportion of the heated gases toward the portion of the oven furthest from the source of theheat and thereby attain uniformity of temperature in the baking chamber.

3. In an oven, 21 horizontally elongated tubular casing having a baking chamber therein and a similarly horizontally elongated passage through the bottom thereof through which the heated gases may enter the baking chamber, a heat spreader supported across the passage within the (Zl1:11l]- her for directing the heated gases to the marginal portions of the chamber, said spreader having a heat deflecting wall encountered by the entering gases and inclined in the direction of the elongation of the passage so that when the heated gases are sup plied. to the portion of the elongated passage adjacent the lowest point of inclination of the deflecting wall, an increased proportion of the gases will be deflected to the further marginal portion of the oven and thereby cause maximum uniformity of temperature in the baking chamber.

4. In an oven, at horizontally elongated tubular casing having a baking chamber thereheated gases are supplied to the portion of.

the elongated passage adjacent the lowest point of inclination of the deflecting wall, an increased proportion of the gases will be 'deflected to the further marginal portion of the oven to thereby obtain maximum uniformity of temperature in the baking chamber, said spreader being removably supported in the casing so as to be replaceable by a spreader which may direct heat uni formly to all marginal portions when the oven is to be used with heated gases coming from two spaced sources through the passage.

5. In an oven, a tubular casing having a passage through the bottom wall thereof into the baking chamber, a sheet metal heat spreader supported in said casing across the passage for deflecting the heat to the marginal portions of the baking chamber, said spreader having a depending marginal flange upon two opposite margins, which rest upon the bottom wall of the baking chamber and support the heat spreader across the passage, the other marginal portions of the spreader being free of depending flanges whereby by reason of its spacing from the bottom wall, the heated gases deflected by the spreader may pass under the unflanged margins into the baking chamber, said spreader having the wall surface encountered by the rising heated gases inclined in a direction to deflect a large portion of the gases toward one portion of the oven.

6. In an oven, a heat spreader of sheet metal, having two opposite marginal portions bent normally thereof to form supporting flanges, said flanges being of greater dimension at one end than at the other, spacing the spreader in nonparallel position from a surface upon which it rests, the other two marginal portions of the spreader being free of flanges so as to be spaced above the plane of the surface upon which the two flanges rest.

7. In an oven, a heat spreader comprising a stretch of sheet metal, a second stretch of sheet metal secured to the underface of. the first sheet with an intermediate portion largely in spaced relation thereto and incline'd in a direction from one marginal portion to the opposite one, in order to direct a larger proportion of the heated gases striking the deflector toward one marginal portion of the spreader.

8. In an oven, a heat spreader comprising a stretch of sheet metal forming a supporting base, a second stretch of sheet metal secured to the nndert'ace ot' the lirst stretch of sheet metal and having its nnde'r'face concave and inclined in a direction transversely of the curvature of the concavity for 'di recting the heat laterally and a considerable portion in the direction of inclination.

9. In an oven, a heat spreader comprising a. stretch of sheet metal forming a supporting plate, a second stretch of sheet metal secured along two of its opposite side margins to the under face of the iirst mentioned sheet, with the portion of the second stretch between the secured margins depending downwardly and then bowed upwardly concavely for deflecting the gases striking the concave portion of the second stretch toward the side margins.

10. in an oven, a heat spreader comprising a stretch of sheet metal, forming a supporting plate, a second stretch of sheet metal cured along two opposite side. margins to the under face of the first mentioned sheet, with the portion of the second stretch be tween the secured margins depending downwardly and then bowed upwardly concavely for deflecting the gases striking the concave portion of the second stretch toward the sccured side margins, the concave intermediate portion of the second stretch being inclined in a direction transverse to the concave curvature between the secured marginal portions thereof, for directing a considerable portion of the hot gases striking the spreader toward one end.

11. In an oven, a horizontally elongated tubular casing having a door in one end of the elongation and having a passage in the bottom through which heated gases may enter the baking chamber, a heat spreader disposed across the passage in the bottom walls for deflecting the heated gases striking the same to the marginal portions of the baking chamber, the spreader having its J; v sides spaced above the oottom wall 01 the chamber and its rear margin apertured, to permit of the pasasge oi' the hot gases from the margins 01' the spreader directly into the baking chamber, the edge portion of the spreader adjacent the door being imperiorate and resting upon the floor of the baking chamber whereby when the door is opened the hot gases will not rush directly out through the open door from said spreader.

12. In an oven, a horizontally elongated tubular casing having a door in one end of the elongation and having a passage in the bottom through which heated gases may enter the baking chamber, a heat spreader disposed across the passage in the bottom of the casing for deflecting the heated gases strikin the same to the marginal portions of the baking chamber, the spreader having its sides spaced above the bottom wall of the chamber and its rear margin apertured to permit oi the passage of the hot gases from the margins oi the spreader directly into the baking chamber the forward margin of the spreader adjacent the door resting upon the bottom of the baking chamber and being imperlorate, whereby when the door is opened the hot gases will not rush directly through the open door from said spreader, said spreader having its lower heat deflecting surface inclined rearwardly in order to direct a considerable portion of the heated gases toward the rear of the baking chamber when they are admitted near the front end.

In witness whereof, I hereunto subscribe my signature.

LEYVIS T. W'ILCOX. 

